A common problem associated with electric utility lines, pipelines, highways, and railroads is that of trees or other plant growth encroaching into the right of way. This encroachment interferes with the activity occurring within the right of way. To alleviate this problem, various methods have been used to clear right of ways of this unwanted growth. A truck has been used in which men are put into a bucket and raised by means of a boom to the area of the unwanted growth. By hand or power saw the men cut the growth from the right of way. This method is undesirable for a number of reasons. First, it is necessary to raise a man off the ground up to the area of the unwanted growth. This can be dangerous in any situation but is especially so in the situation where tree limbs are being trimmed from the area around power lines. A chance of eletrocution exists even if extreme caution is used. Secondly, each time the growth within reach of the bucket is trimmed the bucket must be lowered to its traveling position and the truck moved to the next site. Then it is necessary to again raise the bucket into position for trimming the trees. The setup involved with this process is very time-consuming and consequently this method is undesirable for most right of way clearing applications.
Other devices have been proposed which alleviate some of the problems associated with right way of clearing. It has been proposed to mount some kind of cutting device on the end of a retractable boom which can be controlled by an operator on or near the ground. This boom device is then mounted on a vehicle to give the cutting apparatus mobility. However, these prior devices have all contained one or more undesirable aspects which limit their effective use as a right of way clearing device. For example, many of these devices are constructed so that the boom has a very limited reach. Therefore, these cutting apparatus are ineffective for clearing right of ways where there is very tall tree growth necessitating a long reach. When attempts have been made to extend the reach of the boom in these devices other undesirable side effects have been produced. The extended boom length has added greatly to the weight of the cutting apparatus and it has been necessary to stabilize the device by using outriggers mounted on the sides of the vehicle on which the cutting apparatus is carried. Each time the device is moved the outriggers must be lowered into their stabilizing position. This greatly increases the setup time and thus lowers the efficiency of the device.
Another problem that must be faced when clearing the right of way for high voltage utility lines is that of the potential for electric shock should the boom come into contact with the power lines. The prime objective in this situation is to provide the maximum amount of safety for the operator of the cutting apparatus. Prior art boom tree trimming devices have been unsatisfactory in this respect in that they have been comprised of materials which provide an electrically conductive path between the high voltage lines and the operator. Thus, it has not been safe to use these tree-trimming devices in the proximity of high voltage lines.